1. Field of the Invention
The present invention relates to fine powder of waste polyurethane foam and a method of manufacturing the same, and more particularly, to fine powder of waste polyurethane foam, which is manufactured using a crushing process, including primary and secondary coarse crushing steps and a fine grinding step, and a classification process in a physical powdering technique of waste polyurethane among waste polyurethane recycling techniques, and to a method of manufacturing the same.
2. Description of the Related Art
Generally, polyurethane, which is a polymer of an isocyanate group and a hydroxyl compound, has good tensile strength and elasticity and is also superior with respect to abrasion resistance, oil resistance, and solvent resistance, and thus is applied to foam materials, elastic materials, paints, adhesives, fibers, synthetic leather, and sealing agents. Further, as applications thereof, shoes, construction materials, automobile parts, molded products, and furniture are exemplary. Therefore, polyurethane has been produced into products having various properties by controlling the type and proportion of raw material thereof, and the consumption thereof is increasing every year. However, generation of waste is increasing in proportion to the increase in the use of polyurethane, undesirably incurring environmental problems.
Waste disposal methods that have been developed to date include reclamation methods, incineration methods, and recycling methods. Of these methods, the reclamation method and incineration method are problematic in that environmental contamination occurs and economic benefits are negated. Hence, much research effort has been directed toward the recycling method.
Presently, the recycling method is reported to be exemplified by powdering process, thermal utilization process or polymer regeneration process. Among these, the thermal utilization process is employed in order to obtain predetermined material using thermal energy resource or through pyrolysis, but suffers because the initial facility cost is very high. The powdering process is performed by subjecting waste to collection, crushing and processing to thus recycle it as filler or material. The polymer regeneration process is performed by decrosslinking the crosslinked polymer to thus use it as recycling resin. However, due to many problems relating to economic and technical properties, despite such effort, it is difficult to further develop the recycling techniques.
In particular, according to the powdering technique among the polyurethane recycling techniques, in the case where waste hard polyurethane is crushed to form powder thereof, a process of finely grinding such polyurethane to a size of less than 50 μm is not yet known. Accordingly, through the present techniques for reusing waste polyurethane, waste polyurethane can only be crushed to a particle diameter of 100 μm or greater. In this case, however, the use of such powder having a large particle diameter undesirably results in problems of drastic deterioration of the properties, such as tensile strength, elongation, and repulsive elasticity, and also difficulty in forming a desired cell structure.